Production of ferroboron

ABSTRACT

A process for producing ferroborons is disclosed. The process consists of reacting a boron compound such as calcined colemanite with a metal such as aluminum in the presence of iron. The solid state reaction followed by subsequent grinding and sintering steps optimizes boron recovery.

TECHNICAL FIELD

This invention relates to a process for producing ferroborons. In one embodiment, ferroboron is produced from colemanite or other borates.

BACKGROUND ART

Present technologies produce boron alloys by means of smelting processes that utilize either carbon or aluminum as the reducing agent for boron anhydride, B₂ O₃. The rapidly expanding field is essentially associated with the development of amorphous metals having very low magnetic losses, with typical alloys being Fe--Ni--B and Fe--B--Si. These alloys find their applications in motor and transformer cores and the electronic industry in general.

The standard smelting processes for producing ferroboron alloys seem to have in common a low boron yield that perhaps reflects the relatively high cost of producing the alloy.

The normal starting material for producing ferroboron is boric acid which, upon dehydration, converts to boron anhydride, B₂ O₃. This boron oxide is very stable and can be reduced to metallic boron with carbon, aluminum or magnesium.

Smelting is the general approach to ferroboron production, but process yields are only around 40%. Besides the yield drawback of present smelting practices, carbon reduction produces ferroboron containing approximately 2% carbon; aluminum reduction produces ferroboron containing approximately 1.5% aluminum; and magnesium reduction has inherent high magnesium losses and slag-metal separation difficulties.

DISCLOSURE OF INVENTION

In my scheme to ferroboron alloys production, I have taken an entirely different approach to lower the energy requirements and improve the overall boron yield. My process relies on solid state reactions among colemanite, aluminum and iron to generate primarily ferroborn sintered within a matrix of calcium aluminates. Liberation of the alloy from this matrix and subsequent smelting is seen as an alternative to present smelting practices.

The solid ferroboron is made at low temperatures by solid and liquid state reactions in order to save on energy. It takes advantage of the exothermic heat of reaction to the fullest. The subsequent smelting of the alloy requires, in general, energy only for a fraction of the total feed to the process. Another advantage is that my process does not require highly refined starting materials such as boric acid.

This process consists of reacting a borate with aluminum powder in the presence of iron powder to produce solid ferroboron alloys by solid and liquid state reactions in the temperature range from 700° to 1200° C. hereupon identified as "solid state reactions". Typical reactions are:

    2CaO.3B.sub.2 O.sub.3 +6Al+6Fe⃡6FeB+3Al.sub.2 O.sub.3 +2CaO

    2CaO.3B.sub.2 O.sub.3 +9Mg+6Fe⃡6FeB+2CaO+9MgO

When reducing borates with aluminum, the addition of CaO is beneficial in producing more desirable calcium aluminate species for the mineral processing of the calcine produced or the subsequent smelting of the total sintered mass.

The calcine produced is then crushed and ground to liberate the ferroboron alloys from the calcium aluminates. The ground calcine is then subjected to magnetic separation to recover a concentrate containing the boron-iron alloys. The tails are discarded. The granular magnetic concentrate is then smelted and refined to satisfy end use specifications. This is scheme A in the Figure.

Iron is used as collector for boron, and its proportion can be varied depending upon the grade of ferroalloy required. However, the proportion of iron may be adjusted in order not to sacrifice boron recovery. The aluminum requirement is, in general, 2.5 grams per gram boron present in the process feed as borates. However, the aluminum addition can be reduced in order to decrease the residual Al level in the FeB alloy or it can be increased to improve boron recovery. Instead of Fe as collector, Fe₂ O₃ and/or Fe₃ O₄ and/or FeO can be used with an attendant increase in Al and/or Mg requirements as reductants. The process then is carried out by direct smelting. This is also the case when CaO is added to adjust the CaO-Al₂ O₃ ratio between 0.85 and 1.06. This is scheme B in the FIGURE.

The B₂ O₃ may be supplied by many different borate compounds. The following is a list of some of the more readily available borate compounds:

    ______________________________________                                         Mineral or Chemical Name                                                                          Chemical Formula                                            ______________________________________                                         Boric acid         H.sub.3 BO.sub.3                                            Anhydrous boric acid                                                                              B.sub.2 O.sub.3                                             Anhydrous borax    Na.sub.2 O.2B.sub.2 O.sub.3                                 5 Mol borax        Na.sub.2 O.2B.sub.2 O.sub.3.5H.sub.2 O                      Borax              Na.sub.2 O.2B.sub.2 O.sub.3.10H.sub.2 O                     Dehydrated Rasorite                                                                               Na.sub.2 O.2B.sub.2 O.sub.3                                 Probertite         Na.sub.2 O.2CaO.5B.sub.2 O.sub.3.10H.sub.2 O                Ulexite            Na.sub.2 2CaO.5B.sub.2 O.sub.3.16H.sub.2 O                  Colemanite         2CaO.3B.sub.2 O.sub.3.5H.sub.2 O                            Calcined colemanite                                                                               2CaO.3B.sub.2 O.sub.3.H.sub.2 O                             Sodium Perborate   NaBO.sub.2.H.sub.2 O.sub.2.3H.sub.2 O                       ______________________________________                                    

Because of the disadvantages of relatively large amounts of water or soda in many of these compounds, ulexite, colemanite and especially calcined colemanite are preferred.

BRIEF DESCRIPTION OF THE DRAWING

The FIGURE shows a flow sheet of the process according to this invention.

BEST MODE OF CARRYING OUT INVENTION Thermodynamic Properties

Colemanite is a mineral of composition 2CaO.3B₂ O₃.5H₂ O that upon calcination converts to 2CaO.3B₂ O₃.

The free energy and heat of formation of calcined colemanite were estimated as a linear combination of the properties of two other calcium borates as follows (Kcal):

    ______________________________________                                         Species          ΔG.sub.f 298                                                                     ΔH.sub.f 298                                    CaO.B.sub.2 O.sub.3                                                                             -457.7  -483.3                                                CaO.2B.sub.2 O.sub.3                                                                            -752.4  -798.8                                                2CaO.3B.sub.2 O.sub.3                                                                           -1.210  -1.282                                                Reduction by Aluminum                                                          2CaO.3B.sub.2 O.sub.3 + 6Al                                                                    ⃡2CaO + 3Al.sub.2 O.sub.3 + 6B                                     Δ G = -213 Kcal (Feasible)                                               Δ H = -220 Kcal (Exothermic)                             ______________________________________                                    

The stoichiometric aluminum requirement is 2.5 units per unit weight of boron.

Reduction by Magnesium

2CaO.3B₂ O₃ +9Mg⃡9MgO+2CaO+6B

ΔG=-303 Kcal (Feasible)

ΔH=-386 Kcal (Exothermic)

The stoichiometric magnesium requirement is 3.37 units per unit weight of boron.

Process Impact of Physical Properties

Some of the physical properties of elements and compounds of interest in the reduction of borates are given in Table 1. These properties, in general, will affect the efficiency of the reduction process, the selection of reductant and the choice of equipment to perform the reduction reaction.

To be sure, the presence of water, carbonates and air leakages in the system, for example, will oxidize more drastically Mg than Al. Carbonates will contribute to the level of carbon in the ferroboron alloy depending upon the temperature of reaction. The low melting temperature of colemanite, magnesium and aluminum will induce sintering which brings up the questions of choice between loose or briquetted feed and type of reactor. The low boiling point of magnesium adds to this metal total loss and to the careful design of equipment to prevent fire hazards.

The advantages of aluminum over magnesium concerning its reduced oxidation and volatization losses, and the more favorable stoichiometric requirements and slag characteristics. These facts determined our primary thrust in using aluminum as the reducing agent for colemanite and borates in general.

                  TABLE 1                                                          ______________________________________                                         SOME PHYSICAL PROPERTIES OF ELEMENTS AND                                       COMPOUNDS OF INTEREST                                                          IN FERROBORON PRODUCTION                                                       Species       Process      Temperature, °C.                             ______________________________________                                         2CaO.3B.sub.2 O.sub.3.5H.sub.2 O                                                             Dehydration  315-405                                             2CaO.3B.sub.2 O.sub.3                                                                        Fusion       646                                                 CaCO.sub.3    Decomposition                                                                               860-1,010                                           Mg.sub.(s)    Fusion       650                                                 Mg.sub.(1)    Boiling      1,110                                               Al.sub.(s)    Fusion       660                                                 Al.sub.(1)    Boiling      2,060                                               ______________________________________                                    

Ferroboron Test Procedures

The invention was designed according to the flowsheet shown in the FIGURE. The effort was concentrated on the "solid state" reaction scheme which is identified as branch A on the conceptual flowsheet.

The operating procedures of the "solid state" reaction were as follows:

Materials Specifications. The reduction process was carried out using calcined colemanite as process feed, aluminum powder as reducing agent and iron powder as the collector to form the ferroboron alloys.

The particle size of the calcined colemanite was essentially -65 mesh, and its chemical assays are given below.

    ______________________________________                                         Sample: Calcined Colemanite                                                    Chemical Assay: Wt. %                                                          B     CaO    MgO      Fe   SiO.sub.2                                                                             Al.sub.2 O.sub.3                                                                     CO.sub.2                                                                             LOI                              ______________________________________                                         13.39 35.1   0.34     0.16 1.27   0.16  12.46 12.60                            ______________________________________                                    

The particle size of the aluminum powder was -325 mesh, and the iron powder was investigated in two particle size ranges: -100 mesh and -325 mesh.

The iron ore used for this purpose was the Carol Lake spiral concentrate, sample No. 82-6, ground to -150 mesh and having the following chemistry:

    ______________________________________                                                 Assay: Wt. %                                                           Sample    Fe.sub.T                                                                              SiO.sub.2                                                                               Al.sub.2 O.sub.3                                                                     CaO   MgO  LOI                                 ______________________________________                                         Carol Conc.                                                                              66.18  4.35     0.13  0.14  0.4  0.32                                ______________________________________                                    

The general procedures are as follows:

Loose Charges

1. The calcined colemanite is thoroughly blended with the required amounts of iron and aluminum powders. 2. The loose charges are placed in alumina crucibles and loaded inside the Pereny furnace which had been heated to the desired temperature.

3. After loading several crucibles, the furnace temperature is allowed to come back to the set point temperature. The reaction is then allowed to proceed for a specified length of time.

4. The reaction in step 3 is carried out either under a nitrogen or a CO/CO₂ atmosphere. A total gas flow of 7 lpm was used in all cases. For the tests under the reducing atmosphere, the gas was 70% CO and 30% CO₂.

5. At the end of the reaction period, the rucibles are transferred to a water cooled chamber flushed with 5 lpm nitrogen.

6. The cool reacted charge is crushed to -35 mesh and wet ground at 50% pulp density and 20% ball charge for a specified length of time. The slurry is filtered and the solution sampled for analysis. The filter cake is dried at 110° C. overnight.

7. The dried cake is broken down to -100 mesh and a sample of about 25 grams is taken using a mechanical splitter.

8. The 25-g sample is slurried and fed through a series arrangement of two magnetic separators. The first separator is a Davis Tube operating at 6,000 gauss while the second, a Carpco separator, is opeated at 10,000 gauss.

9. The magnetic and non-magnetic products are dried, pulverized and submitted for chemical and X-ray analyses.

10. A material balance on boron is calculated for each test.

Briquetted Charges

1. The calcined colemanite is thoroughly blended with the required amounts of iron and aluminum powders.

2. The blend is briquetted by applying a pressure of 30,000 psi in a single die mold.

3. The briquettes are then allowed to react using either the Pereny furnace, a rotary glass drum or an induction furnace.

4. The testing procedure is contined as in the case for loose charges.

Similar experimental procedures were followed for loose and briquetted charges when iron oxides and/or CaO were used as components of the blend.

The use of Fe₂ O₃, and iron oxides in general, had the dual purpose of generating the metallic iron to collect the boron produced by aluminum reduction, as well as providing for some FeO to flux the slag to reasonable melting temperatures. The effect of CaO was to provide a fluxing action by shifting the CaO--Al₂ O₃ ratio within the range of 0.85 to 1.1.

To carry out the ferroboron generating reactions, the reactors used were a muffle furnace for crucible test, a rotary glass drum to simulate the rotary kiln operation with briquetted charges and an induction furnace for the smelting of briquetted charges.

INDUSTRIAL APPLICABILITY

The following examples are given to illustrate the advantages of the invention but should not be construed as limiting in scope.

EXAMPLE SET 1

The effects of temperature and addition levels of Al and Fe on loose charges under a nitrogen atmosphere are summarized in Table 2. These data simply indicate that ferroboron alloys can be made at temperatures well below the fusion temperature of the slag forming constituents. Major constituents of the Davis Tube Concentrate, DTC, were FeB and Fe₂ B.

EXAMPLE SET 2

These tests summarize the reduction performance of several borate species at high levels of iron addition under a nitrogen atmosphere. These tests were carried out on loose charges, and the results are given in Table 3.

EXAMPLE SET 3

These tests describe the reduction behavior of colemanite under a strongly reducing CO--CO₂ atmosphere at high levels of iron. The difference between a stagnant and a dynamic atmosphere is characterized by the results of crucibles and rotary glass drum respectively. The data are given in Table 4.

This data shows that because of the high oxygen affinity of aluminum, the use of even a reducing direct fired fossil fuel reactor is not possible, but external firing with an internal inert atmosphere remains a choice.

EXAMPLE SET 4

These tests describe the effects of temperature and the addition levels of Al, Fe and CaO under a reducing CO--CO₂ atmosphere. The high levels of iron produce 4 to 6% ferroboron alloys in the Davis tube concentrate, DTC. These data are given in Table 5.

EXAMPLE SET 5

These tests summarize the behavior of colemanite reduction with Mg under a reducing CO--CO₂ atmosphere in the presence of metallic iron or ferric iron oxide. For more efficient use of the Mg reductant, the reaction must be carried out in an inert atmosphere to avoid unnecessary Mg combustion. The experimental data are given in Table 6.

EXAMPLE SET 6

These tests describe the behavior of colemanite reduction by aluminum in the presence of ferric oxide and coal under a reducing CO--CO₂ atmosphere. The data are given in Table 7. These results indicate that the use of iron oxides requires the technique of direct smelting due to low melting point of the fluxed charge. The possibility of partially substituting aluminum with carbon is not a feasible approach.

EXAMPLE SET 7

These tests show the feasibility of ferroboron production from colemanite by direct smelting in the presence of iron oxides and/or calcium oxide under a nitrogen atmosphere. The data are shown in Table 8.

                                      TABLE 2                                      __________________________________________________________________________     FERROBORON FROM COLEMANITE USING LOOSE CHARGES                                 Tests Performed in Alumina Crucibles                                                                                    Atmosphere: Nitrogen (7 1 pm                                                   thru Pereney)                         Reaction Time = 90 Minutes               Colemanite Weight: 100 Grams                            MILL                                                                               Magnetic Boron Assays:                                           Reagents,                                                                            Cal-                                                                               Vol-                                                                               Separation                                                                              gpl or Wt. %              Boron                 Test                                                                               Temp.,                                                                             Grams cine                                                                               ume,                                                                               Wt. Dist.: %                                                                            Solu-       Boron Distribution:                                                                          Accounted             No. C   Al Fe Grams                                                                              Liters                                                                             DTC                                                                               DTT   tion                                                                              DTC DTT  Solution                                                                            DTC                                                                               DTT   %                     __________________________________________________________________________     2-1 732 45 40 182.3                                                                              1.5 42.11                                                                             57.89 0.1                                                                               11.9                                                                               5.6  1.79 59.64                                                                             38.57 108.5                 2-2 800 40 30 162.87                                                                             1.6 31.38                                                                             68.62 0.1                                                                               7.47                                                                               6.4  2.32 33.99                                                                             63.69 79.5                  2-3 800 50 30 183.21                                                                             1.3 36.21                                                                             63.79 0.13                                                                              9.50                                                                               6.4  2.20 44.72                                                                             53.08 99.64                 2-3.sup.(1)                                                                        800 50 30         41.73                                                                             20.36/37.91                                                                          0.13                                                                              5.12                                                                               6.55/4.52                                                                           3.16 39.92                                                                             24.91/32.01                                                                          69.07                 2-4 800 40 50 187.6                                                                              1.5 47.66                                                                             52.34 0.11                                                                              6.82                                                                               6.08 2.50 49.27                                                                             48.23 86.36                 2-5 800 50 50 201.4                                                                              1.7 48.72                                                                             51.28 0.13                                                                              5.75                                                                               5.28 3.85 48.89                                                                             47.26 80.83                 2-6 900 36.6                                                                              40 170.5                                                                              1.9 32.36                                                                             67.64 0.10                                                                              14.9                                                                               4.48 2.36 59.96                                                                             37.68 96.98                 2-7 900 53.41                                                                             40 192.0                                                                              1.8 33.62                                                                             66.38 0.04                                                                              11.4                                                                               5.76 0.93 49.59                                                                             49.48 105.51                2-8 900 45 21.83                                                                             164.3                                                                              1.9 51.50                                                                             48.50 0.08                                                                              10.2                                                                               4.32 2.03 70.04                                                                             27.93 87.32                 2-9 900 45 56.82                                                                             201.0                                                                              1.2 30.72                                                                             69.28 0.07                                                                              9.73                                                                               5.6  1.21 42.99                                                                             55.80 99.21                 2-10                                                                               900 45 40 176.33                                                                             1.9 45.37                                                                             54.63 0.09                                                                              10.2                                                                               4.8  2.30 62.36                                                                             35.34 92.5                  2-11                                                                               900 45 40 177.18                                                                             1.5 33.37                                                                             66.63 0.06                                                                              10.4                                                                               4.96 1.31 50.55                                                                             48.14 86.39                 2-12                                                                               900 45 40 177.3                                                                              1.7 35.20                                                                             64.70 0.09                                                                              9.97                                                                               4.32 2.37 54.35                                                                             43.28 80.94                 2-13                                                                               900 45 40 177.0                                                                              2.0 33.62                                                                             66.38 0.05                                                                              10.4                                                                               4.8  1.47 51.55                                                                             46.98 85.2                  2-14                                                                               900 45 40 177.47                                                                             1.6 46.50                                                                             53.50 0.06                                                                              10.2                                                                               3.84 1.39 68.80                                                                             29.81 86.85                 2-15                                                                               900 45 40 177.75                                                                             1.6 42.43                                                                             57.57 0.08                                                                              9.5 4.16 1.95 61.50                                                                             36.55 82.5                  2-16                                                                               1000                                                                               40 30 163.86                                                                             1.8 32.11                                                                             67.89 0.08                                                                              10.9                                                                               4.64 2.12 51.52                                                                             46.36 78.86                 2-16.sup.(3)      1.0 28.42                                                                             -- /71.58                                                                            0.11                                                                              11.8                                                                               --/3.18                                                                             4.31 57.00                                                                             38.69 72.0                  2-17                                                                               1000                                                                               50 30 174.42                                                                             1.5 33.05                                                                             66.95 0.05                                                                              8.14                                                                               4.96 1.23 44.20                                                                             54.57 75.42                 2-18                                                                               1000                                                                               40 50 183.57                                                                             1.4 47.02                                                                             52.98 0.09                                                                              9.97                                                                               4.48 1.75 65.22                                                                             33.03 93.46                 2-18.sup.(3)      1.0 43.15                                                                             --/56.85                                                                             0.11                                                                              10.10                                                                              --/2.79                                                                             3.82 70.52                                                                             25.66 84.67                 2-19                                                                               1000                                                                               50 50 197.22                                                                             1.2 40.13                                                                             59.87 0.08                                                                              7.92                                                                               5.6  1.45 47.96                                                                             50.59 92.69                 2-20                                                                               1068                                                                               45 40 178.66                                                                             1.5 41.17                                                                             58.8  0.05                                                                              9.88                                                                               4.10 1.14 62.06                                                                             36.80 83.21                 2-21                                                                               1068.sup.(2)                                                                       45 40 183.97                                                                             1.4 37.90                                                                             62.10 0.06                                                                              9.89                                                                               5.51 1.16 51.67                                                                             47.17 94.82                 2-21                                                                               1068.sup.(1)                                                                       45 40     1.4 41.82                                                                             11.75/46.43                                                                          0.06                                                                              7.62                                                                               5.6/3.99                                                                            1.45 55.12                                                                             11.38/32.05                                                                          75.46                 __________________________________________________________________________      Notes:                                                                         .sup.(1) These calcines were reground and evaluated through a Davis            TubeCarpco separation. The figures under DTT separated by a slash actuall      represent the Carpco concentrate and tail respectively. Reground in 3"         × 6" with 12% ball charge @ 50% pulp density for 15 minutes.             .sup.(2) Beginning with this test, the iron used as collector for boron        was -100 mesh rather than -325 M previously used.                              .sup.(3) Reground in 6"  × 6" mill with 20% ball charge @ 50% pulp       density for 15 minutes.                                                        DTC = Davis Tube Concentrate                                                   DTT = Davis Tube Tail                                                    

                                      TABLE 3                                      __________________________________________________________________________     FERROBORN FROM SEVERAL BORATES                                                 Tests Performed in Alumina Crucibles Using Excess Iron                         Reaction Time = 90 Minutes                        Atmosphere: Nitrogen         Charges: Loose                                    Borate Weight: 100                                                             Grams                                          MILL*          Boron Assays:                                         Reagents, Grind                                                                               Magnetic Separation                                                                      gpl or Wt. % Boron Distribution:                                                                       Boron                 Test                                                                               Temp.,                                                                             Grams                                                                               Calcine                                                                             Solution,                                                                           Wt. Dist.: %                                                                             MILL         MILL       Accounted             No. C   Al                                                                               Fe Grams                                                                               Liters                                                                              DTC  DTT  Solution                                                                             DTC                                                                               DTT Solution                                                                            DTC                                                                               DTT                                                                               %                     __________________________________________________________________________     3-22.sup.(1)                                                                       900 45                                                                               100                                                                               238.7                                                                               3.5  80.63                                                                               19.37                                                                               0.04  5.18                                                                              3.56                                                                               2.80 83.43                                                                             13.77                                                                             83.96                 3-23.sup.(1)                                                                       900 45                                                                               150                                                                               290.53                                                                              2.2  84.09                                                                               15.91                                                                               0.06  4.28                                                                              2.72                                                                               3.17 86.44                                                                             10.39                                                                             84.64                 3-24.sup.(2)                                                                       900 45                                                                               150                                                                               275.44                                                                              2.4  82.80                                                                               17.20                                                                               0.4   3.41                                                                              1.78                                                                               23.47                                                                               69.04                                                                              7.49                                                                             81.19                 3-25.sup.(3)                                                                       900 45                                                                               150                                                                               280.46                                                                              2.2  76.04                                                                               23.96                                                                               0.07  3.84                                                                              3.23                                                                               4.00 75.89                                                                             20.11                                                                             98.22                 __________________________________________________________________________      Notes:                                                                         .sup.(1) Tests 322 and 323 were run using 100g colemanite analyzing 14.0%      boron.                                                                         .sup.(2) Test 324 was run using 100g Na.sub.2 B.sub.4 O.sub.7.10H.sub.2 O      analyzing 11.8% boron.                                                         .sup.(3) Test 325 was run using 100g probertite analyzing 10.7% boron.         Significant swelling of the charge occured.                                     *Calcines were actually ground in 6" × 6" mill with 20% ball charg      @ 50% pulp density for 30 minutes.                                             DTC = Davis Tube Concentrate                                                   DTT = Davis Tube Tail                                                    

                                      TABLE 4                                      __________________________________________________________________________     FERROBORON FROM COLEMANITE                                                                                                   Atmosphere: 70% CO & 30%                                                       CO.sub.2                         Reaction Time = 90 Minutes                    Colemanite Weight: 100                                                         grams                                           MILL*                                                                  Rea-    Grind                                                                              Magnetic Separation                                                                       Boron Assays:                                           gents,                                                                             Cal-                                                                               Vol-                                                                               Wt. Distribution: %                                                                       gpl or Wt. % Boron Distribution:                                                                          Boron                 Test                                                                              Temp.,                                                                             Grams                                                                              cine                                                                               ume,   Carpco                                                                             Carpco                                                                             MILL   Carpco                                                                               MILL   Carpco Accounted             No.                                                                               °C.                                                                         Al Fe                                                                              Grams                                                                              Liters                                                                             DTC                                                                               Conc.                                                                              Tail                                                                               Sol.                                                                               DTC                                                                               Conc. Tail                                                                           Sol.                                                                               DTC                                                                               Conc.                                                                              Tail                                                                              %                     __________________________________________________________________________     A. Loose Charges Reacting in Crucibles.                                        4-26                                                                              800.sup.(1)                                                                        35100                                                                              230.48                                                                             1.4 78.26                                                                             7.39                                                                               14.35                                                                              0.14                                                                               5.54                                                                              5.951.42                                                                             3.79                                                                               83.78                                                                             8.50                                                                               3.93                                                                              83.36                 4-26                                                                              800.sup.(6) 2.4 65.44                                                                             0.39                                                                               34.17                                                                              0.14                                                                               5.26                                                                              4.87  6.15                                                                               63.39  30.46                                                                             86.80                 4-27                                                                              800.sup.(1)                                                                        40100                                                                              235.4                                                                              1.2 83.46                                                                             7.87                                                                               8.67                                                                               0.08                                                                               5.54                                                                              5.952.09                                                                             1.79                                                                               86.12                                                                             8.72                                                                               3.37                                                                              89.35                 4-28                                                                              900 35100                                                                              233.41                                                                             1.45                                                                               66.39                                                                             0.52                                                                               33.09                                                                              0.14                                                                               5.44                                                                              4.50  3.96                                                                               70.97  25.07                                                                             83.57                 4-29                                                                              900 40100                                                                              240.1                                                                              1.0 63.35                                                                             0.49                                                                               36.16                                                                              0.13                                                                               4.94                                                                              3.93  2.76                                                                               67.03  30.21                                                                             79.39                 4-30                                                                              900.sup.(2)                                                                        40100                                                                              229.96                                                                             1.15                                                                               62.38                                                                             1.25                                                                               36.37                                                                              0.06                                                                               4.60                                                                              5.49  1.38                                                                               58.63  39.99                                                                             81.36                 4-31                                                                              800.sup.(3)                                                                        35100                                                                              228.08                                                                             1.1 40.99                                                                             0.46                                                                               58.55                                                                              0.11                                                                               0.88                                                                              7.19  2.54                                                                                9.13  88.33                                                                             76.54                 4-32                                                                              800 40100                                                                              238.47                                                                             1.15                                                                               63.84                                                                             0.46                                                                               35.7                                                                               0.13                                                                               4.54                                                                              3.90  3.35                                                                               65.44  31.21                                                                             74.5                  B. Briquetted Charges Reacting in Rotary Glass Drum, RGD.                      4-7.sup.(4)                                                                       800 40100                                                                              234.61                                                                             4.6 41.20                                                                             12.54                                                                              46.26                                                                              0.07                                                                               1.84                                                                              5.995.47                                                                             7.4 17.07                                                                             17.29                                                                              58.24                                                                             72.8 RGD              4-8.sup.(4)                                                                       900 40100                                                                              233.91                                                                             3.1 37.67                                                                             1.09                                                                               61.24                                                                              0.15                                                                               1.26                                                                              4.83  11.89                                                                              12.49  75.62                                                                             63.63 RGD             C. Test to Elucidate Behavior of Section B Above, Uring Briquettes in          Crucibles & Rotary Drum.                                                       4-47.sup.(5)                                                                      900 40100                                                                              252.38  85.60                                                                             0.42                                                                               13.98   4.97                                                                              2.57      92.25  7.75                                                                              83.55                 4-47.sup.(6)   2.6 59.98                                                                             0.52                                                                               39.50                                                                              0.14                                                                               5.09                                                                              4.16  7.2 60.33  32.47                                                                             87.26                 4-9.sup.(5)                                                                       900 40100                                                                              232.0   76.21                                                                             0.51                                                                               23.28   4.61                                                                              4.30      77.94  22.06                                                                             75.20                 4-9.sup.(6)    7.5 42.07                                                                             0.62                                                                               57.31                                                                              0.07                                                                               2.18                                                                              6.41  10.24                                                                              18.14  71.62                                                                             80.05                 __________________________________________________________________________                                                              RGD                    Notes:                                                                         .sup.(1) Heat of reaction temporarily overheated calcine to 1000°       C. (2 minutes).                                                                .sup.(2) Test reaction time was 15 minutes.                                    .sup.(3) Charge reacted partially.                                             .sup.(4) Calcines were ground in 6" × 3" steel mill with 12% ball        charges @ 50% pulp density for 30 minutes.                                     .sup.(5) Calcines were dry ground in Shatterbox.                               .sup.(6) Calcines were reground in 6" × 6" steel mill with 20% ball      charge @ 25% pulp density for 15 minutes.                                      *Calcines were generally ground in 6" × 6" steel mill with 20% ball      charge @ 50% pulp density for 30 minutes                                       DTC = Davis Tube Concentrate                                             

                                      TABLE 5                                      __________________________________________________________________________     FERROBORON FROM COLEMANITE                                                     WITH CaO ADDITION                                                              Reaction Time = 90 Minutes                    Atmosphere: 70% CO & 30%                                                       CO.sub.2                         Charges: Loose                                Colemanite Weight: 100                                                         grams                                                   Magnetic                                                                   MILL*                                                                              Separation                                                                 Grind                                                                              Wt. Distribution:                                                                       Boron Assays:             Boron                       Reagents,                                                                              Cal-                                                                               Vol-                                                                               %        gpl or Wt. % Boron Distribution:                                                                         Ac-                  Test                                                                              Temp.,                                                                             Grams   cine                                                                               ume,   CARPCO                                                                               MILL   CARPCO                                                                               MILL   CARPCO                                                                               counted              No.                                                                               °C.                                                                         Al                                                                               Fe CaO                                                                               Grams                                                                              Liters                                                                             DTC                                                                               Conc. Tails                                                                          Sol.                                                                               DTC                                                                               Conc. Tail                                                                           Sol.                                                                               DTC                                                                               Conc.                                                                                %ail                 __________________________________________________________________________     5-39                                                                               900                                                                               35                                                                                75                                                                               23 229.60                                                                             1.3 50.63                                                                             0.7448.63                                                                            0.06                                                                               5.75                                                                              --4.85                                                                               1.45                                                                               54.80                                                                             --43.75                                                                              87.19                5-40                                                                               900                                                                               35                                                                               100                                                                               23 255.78                                                                             1.3 54.75                                                                             0.7644.49                                                                            0.07                                                                               4.58                                                                              --5.27                                                                               1.83                                                                               51.07                                                                             --47.10                                                                              89.94                5-41                                                                               900                                                                               40                                                                                75                                                                               35 261.17                                                                             1.0 61.34                                                                             0.0838.58                                                                            0.03                                                                               4.58                                                                              --3.76                                                                               0.7 65.52                                                                             --33.78                                                                              79.75                5-42                                                                               900                                                                               40                                                                               100                                                                               35 281.67                                                                             1.4 63.87                                                                             0.3935.74                                                                            0.04                                                                               4.29                                                                              --4.17                                                                               1.31                                                                               64.06                                                                             --34.63                                                                              85.85                5-43                                                                              1000                                                                               35                                                                                75                                                                               23 241.28                                                                             1.2 43.67                                                                             0.3555.98                                                                            0.16                                                                               5.02                                                                              --4.59                                                                               3.88                                                                               44.45                                                                             --51.67                                                                              83.74                5-44                                                                              1000                                                                               35                                                                               100                                                                               23 266.39                                                                             1.2 59.13                                                                             --40.87                                                                              0.17                                                                               4.88                                                                              --4.85                                                                               4.03                                                                               56.89                                                                             --39.08                                                                              94.08                5-45                                                                              1000                                                                               40                                                                                75                                                                               35 262.08                                                                             1.0 44.59                                                                             0.0655.35                                                                            0.18                                                                               4.73                                                                              --4.76                                                                               3.65                                                                               42.87                                                                             --53.48                                                                              90.14                5-46                                                                              1000                                                                               40                                                                               100                                                                               35 284.12                                                                             1.2 49.98                                                                             0.2249.8                                                                             0.12                                                                               4.15                                                                              --5.53                                                                               2.89                                                                               41.82                                                                             --55.29                                                                              99.20                __________________________________________________________________________      *Calcines were actually ground in 6" × 6" steel mill with 20% ball       charge @ 50% pulp density for 30 minutes.                                      DTC = Davis Tube Concentrate                                             

                                      TABLE 6                                      __________________________________________________________________________     FERROBORON FROM COLEMANITE                                                     MAGNESIUM REDUCTION.sup.(1)                                                    Reaction Time = 90 Minutes                                                     Charges: Loose                                Atmosphere: 70% CO & 30%                                                       CO.sub.2                                                 Magnetic                                                                   MILL*                                                                              Separation                                                     Reagents,   Grind                                                                              Wt. Distribution:                                                                       Boron Assays:            Boron                        Grams   Cal-                                                                               Vol-                                                                               %        gpl or Wt. % Boron Distribution:                                                                        Ac-                  Test                                                                               Temp.,                                                                             Carol   cine                                                                               ume    Carpco                                                                               MILL   Carpco                                                                               MILL  Carpco                                                                               counted              No. °C.                                                                         MgFeConc.                                                                              Grams                                                                              Liters                                                                             DTC                                                                               Conc. Tail                                                                           Sol DTC                                                                               Conc. Tail                                                                           Sol. DTC                                                                             Conc.                                                                                %ail                 __________________________________________________________________________     6-48                                                                               900 47.2 100 --                                                                            263.06                                                                             1.2 49.44                                                                             --50.56                                                                              0.22                                                                               2.77                                                                              --3.81                                                                               7.42 38.47                                                                           --54.11                                                                              63.8                 6-49.sup.(2)                                                                       900 56.5 -- 75                                                                             162.6?                                                                             1.0 65.20                                                                             --34.8                                                                               0.11                                                                               3.55                                                                              --2.40                                                                               3.38 71.00                                                                           --25.62                                                                              74.74                6-50.sup.(3)                                                                       900 64.0 -- 60                                                                             174.34?                                                                            1.0 61.86                                                                             --38.14                                                                              0.15                                                                               5.42                                                                              --2.32                                                                               3.42 76.41                                                                           --20.17                                                                              67.30                __________________________________________________________________________      NOTES:                                                                         .sup.(1) A very violent reaction developed, more likely as a result of th      reaction between Mg, Fe.sub.2 O.sub.3 and the CO/CO.sub.2 atmosphere. The      crucibles were shattered and a satisfactory recovery of the calcines was       not possible, especially for tests 649 and 50.                                 .sup.(2) Colemanite weight was 50 grams rather than the standard 100           grams.                                                                         .sup.(3) Colemanite weight was 80 grams rather than the standard 100           grams.                                                                         *Calcines were actually ground in a 6" × 6" steel mill with 20% bal      charge @ 50% pulp density for 30 minutes.                                      DTC = Davis Tube Concentrate                                             

                                      TABLE 7                                      __________________________________________________________________________     FERROBORON FROM COLEMANITE IN THE                                              PRESENCE OF IRON OXIDES & COAL                                                                                               Atmosphere: 70% CO & 30%                                                       CO.sub.2                         Reaction Time = 60 Minutes                    Colemanite Weight: 100                                                         Grams                                                     Magnetic                                                      Reagents, Grams                                                                             MILL*                                                                              Separation                                                          Co-    Grind                                                                              Wt. Distribution:                                                                       Boron Assays:           Boron                           Car-                                                                              lom-                                                                              Cal-                                                                               Vol-                                                                               %        gpl or Wt. %                                                                               Boron Distribution:                                                                        Ac-                  Test                                                                               Temp., ol bian                                                                              cine                                                                               ume    Carpco                                                                               MILL  Carpco                                                                               MILL  Carpco                                                                               counted              No. °C.                                                                         Al Conc                                                                              Coal                                                                              Grams                                                                              Liters                                                                             DTC                                                                               Conc. Tail                                                                           Sol. DTC                                                                             Conc. Tail                                                                           Sol. DTC                                                                             Conc.                                                                                %ail                 __________________________________________________________________________     A. Loose charge of feed blend was reacted in the Pereney furnace using         open crucibles.                                                                7-33                                                                               900.sup.(1)                                                                        83.5                                                                              150                                                                               -- Lost (Test was lost due to broken crucible by violent                          reaction.)                                                    (90                                                                            Min.)                                                                          7-34                                                                               900.sup.(1)                                                                        59.0                                                                                75.0                                                                            -- 221.0                                                                              1.25                                                                               30.10                                                                             --69.9                                                                               0.10 11.0                                                                            --2.04                                                                               2.57 68.10                                                                           --29.33                                                                              75.7                 (90                                                                            Min.)                                                                          B. Briquetted charge of feed blend was reacted in the Pereney furnace          using open crucibles. Only a fraction of the blend was used.                   7-35                                                                               900.sup.(1)                                                                        83.5                                                                              150                                                                               -- Lost                                                                     Met-                                                                              But-                                                                               98.4             7.82       55.00                                       al ton                                                              7-36                                                                               900 59  75                                                                               -- 164.41                                                                             1.68                                                                                8.39                                                                             --91.61                                                                              0.10  7.66                                                                           --2.00                                                                               1.52  9.6                                                                            27.36 78.64                           Met-                                                                              But-                                                                               56.54  95.39                                                                             -- 4.61                                                                              12.10 --9.45                                                                               59.28 -- 2.24                               al ton                 Overall Recoveries                                                                         1.52 68.88                                                                           29.6                       7-37                                                                               900 35 150                                                                               45 261.85                                                                             2.2 14.85                                                                             --85.15                                                                              0.08  2.75                                                                           -- 5.88                                                                              3.15  7.3                                                                            --89.55                                                                              102.5                7-38                                                                               900 35  75                                                                               22.5                                                                              202.28                                                                             1.9 31.98                                                                             5.262.82                                                                             0.14  7.33                                                                           --3.91                                                                               4.88 50.03                                                                           --45.09                                                                              76.8                 __________________________________________________________________________      NOTES:                                                                         .sup.(1) The thermite reaction was quite violent, resulting in fusion of       the charge and loss of Test 733 and 35 due to reacted crucible.                *Calcines were ground in the 6" × 6" steel mill with 20% ball charg      @ 50% pulp density for 30 minutes.                                             DTC = Davis Tube Concentrate                                             

                                      TABLE 8                                      __________________________________________________________________________     FERROBORON BY DIRECT SMELTING                                                                                                      Atmosphere: Nitrogen              Blend                Products    Wt.  Assays:                                                                               Boron                                                                               Boron                 Test                                                                              Temp.,         Carol            Amount                                                                              Distri-                                                                             gpl or Wt.                                                                            Distri-                                                                             Accounted             No.                                                                               °C.                                                                         Colemanite                                                                           Al Fe                                                                               Conc.                                                                              CaO                                                                               CaF.sub.2                                                                         Name   Grams                                                                               bution %                                                                            B  Al  bution                                                                              %                     __________________________________________________________________________     8-1.sup.(1)                                                                       1650                                                                                40   20 20                                                                               --  -- 20 Calcine                                                                               88.7                                                                    DTC         43.94                                                                               10.9                                                                              --  75.9                                                   DTT         56.06                                                                               2.08                                                                              --  18.5                       8-2.sup.(1)                                                                       1650                                                                                40   20 20                                                                               --  20 20                                                                                DTC         39.74                                                                               10.4                                                                              --                                                         CTT         60.26                                                                               2.08                                                                              --                             83.sup.(2)                                                                        1650                                                                               (Composite of DTC from Tests 2-6 thru 21)                                                           HD. Compo                                                                             52.9 100.0                                                                               8.93                                                                              0.64                                                       Met. Button      13.3                              8-4.sup.(3)                                                                       1350                                                                               100   83.5                                                                              --                                                                               150 -- -- Calcine                                                                               367.04                                                                  Met. Button                                                                           109.39                                                                              29.8 7.31                                                                              7.09                                                                               59.69                                                                               94.8                                              DTC         3.43 2.46   2.31                                                   Carpco Tail 66.76                                                                               2.01   36.78                                                  Grind Vol.                                                                            1.5.sup.(1)                                                                              0.03   1.22                       8-5.sup.(3)                                                                       1600                                                                               100   35 75                                                                               --  23 -- Calcine                                                                               294.18                100.3                                             Met. Button                                                                           80.12                                                                               27.24                                                                               10.8                                                                              0.265                                                                              61.43                                                  DTC         2.62 7.56   4.14                                                   Carpco Tail 70.14                                                                               2.32   33.98                                                  Grind Vol.                                                                            1.1.sup.(1)                                                                              0.02   0.45                       __________________________________________________________________________      NOTES:                                                                         .sup. (1) Attempts to smelt without the use of CaO and/or FeO. The charge      showed signs of incipient fusion but the crucibles broke and tests were        lost. Partial evaluation was done to get an indication of possible             recovery.                                                                      .sup.(2) This was an attempt to smelt a Davis Tube concentrate composite.      A metal bottom was recovered but the charge did not melt and the crucible      was destroyed by heat & chemical reation.                                      .sup.(3) These were smelting tests using fluxes to drop the melting point      of the slag. A double crucible arrangement was used in these tests in an       effort to obtain a material balance.                                           DTC = Davis Tube Concentrate                                                   DTT = Davis Tube Tail                                                     

I claim:
 1. A process for producing ferroboron including the step of reducing borate compounds with a material selected from the group consisting of uncombined aluminum, aluminum oxide, uncombined magnesium, and magnesium oxide in the presence of iron under an inert atmosphere at temperatures below the fusion temperature of slag forming constituents.
 2. A process according to claim 1 wherein the reaction is carried out at temperatures ranging from 700° to 1200° C.
 3. A process according to claim 1 wherein the reaction is carried out at 950° C.
 4. A process according to claim 1 wherein the borates compounds are calcium borates.
 5. A process according to claim 1 wherein the borate compounds are colemanite or calcined colemanite.
 6. A process for producing ferroboron including the step of reducing calcium borates with aluminum powder in the presence of iron or iron oxide powders under an inert atmosphere at temperatures below the fusion temperature of slag forming constituents.
 7. A process according to claim 6 wherein the reaction is carried out at 950° C.
 8. A process according to claim 6 wherein the reaction is carried out with the addition of calcium oxide.
 9. A process according to claim 6 wherein the calcium borates are colemanite or calcined colemanite.
 10. A process according to claim 6 wherein the resulting products are crushed and ground to aid in the separation of the resulting ferroboron and resulting calcium aluminate.
 11. A process according to claim 9 wherein the ground products are subjected to magnetic separation and the magnetic concentrate is smelted.
 12. A process according to claim 6 wherein the reaction is carried out at temperatures ranging from 700° to 1200° C.
 13. A process according to claim 6 wherein the inert atmosphere is nitrogen or argon.
 14. A process according to claim 1 wherein the solid state reactions are represented by the equation: 2CaO.3B₂ O₃ +6Al+6Fe⃡6FeB+3Al₂ O₃ +2CaO.
 15. A process according to claim 1 wherein the solid state reactions are represented by the equation: 2CaO.3B₂ O₃ +9Mg+6Fe⃡6FeB+2CaO+9MgO.
 16. A process according to claim 8 wherein the resulting reacted solid mass is heated to 1600° C. to produce a gravity separation of liquid ferroboron alloy from molten slag.
 17. A process according to claim 8 wherein the calcium oxide addition is made in order to produce a CaO--Al₂ O₃ ratio in the range of 0.85 to 1.1 and preferably around 0.85.
 18. A process according to claim 8 wherein the calcium borates may contain calcium carbonates.
 19. A process according to claim 16 wherein the aluminum content of the ferroboron is minimized by increasing the contacting surface area between the molten ferroboron and slag by induction stirring.
 20. A process according to claim 19 wherein the control of residual aluminum can be supplemented by making the slag slightly oxidizing with the addition of Fe₂ O₃ in the final stages of smelting. 